IMC has developed novel 60 µm thin non-reinforced block copolymer anion exchange membrane with good mechanical properties, high conductivity (˃ 50 mS cm-1) and low area specific resistance, ASR (< 0.07 Ω cm²), at room temperature. Highly conductive binder, based on the same chemistry, was also developed and its binding capability for used catalyst, as well as high ionic conductivity, was proved. Stability tests showed high hydroxide stability.
KIST also developed AEM reinforced with an electrospun polybenzimidazole nanofiber mat. The special feature is that the support/matrix interface is strengthened by covalent bonds, which is expected to prevent delamination and thus decreases gas crossover during hydrogen production. In addition, KIST developed a method to reduce the membranes’ dimensional changes during assembly and start of an electrolyzer, by pre-swelling membranes with a mixture of water and a high-boiling solvent.
Ion exchange capacity measurement was acquired and optimized based on the UCTP procedure by the detection of the nitrate ions by UV-VIS spectroscopy. UCTP implemented the method of the true hydroxide conductivity of AEM measurement.
Membrasenz works on membrane upscaling with material and processes which hold potential to be rapid, cost effective and suitable for production of large material quantities.
CENmat upscaled the synthesis of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalyst free of any critical raw materials and performed multiple tests to determine the catalyst performance in various AEM electrolyser cell configurations in different KOH concentrations. Furthermore, CENmat designed and synthesized various other OER and HER catalysts free of CRM.
The potential of the CENmat non-noble metal catalyst was demonstrated in CENmat test cell using commercial AEM, ionomer and PTL. In 0.1 M KOH 1.85 V @ 2 A/cm² was achieved.
For a porous transport layer with optimized gas and liquid transport properties and reduced electrical contact resistance plasma-spray coated Nickel microporous layer (MPL) on stainless steel mesh was prepared at DLR. Due to the MPL a reduction of cell voltage was demonstrated.
The methods of direct deposition of the catalyst layers on the surface of the AEM using sonicated dispersion deposition, automatic spray coating, doctor-blade coating and decal method were successfully modified to allow the catalyst coated membrane electrode assembly preparation. The processes were optimized in terms of catalyst layer composition. However, the performance of these CCM (catalyst coated membrane) electrodes was far from the NEWELY target in water and also in 0.1M KOH. So the focus of the project was on CCS (catalyst coated substrate) electrodes and operation in very dilute 0.1M KOH.
Testing at single cell and stack level processes was agreed with the other two consortia involved in AEM WE technology. A sensitivity study with interesting results to the components that constitute the MEA was carried out. Full NEWELY components MEA (IMC-CAS membrane and ionomer and CENmat catalyst) have achieved in the 25cm² test cell designed by ProPuls 1.5 A/cm²@2V in 0.1 M KOH and 50°C. A long term test of 780 hours in 2 cm² cell and 368 hours in 25 cm² cell were performed. The latter showed an average degradation rate of 28 µV/h and was terminated only due to a test station failure.
The AEMWE test cells designed by ProPuls with 25cm² area based on a patented hydraulic cell compression system were designed, built, delivered to and commissioned at the research partners for component testing and material screening. The cell is close in design to the final stack and allows to evaluate all components relevant for the stack. A test station for laboratory-scale test cells for the usage of ultra-pure water and optional KOH was developed and set up at the FBK lab.
A novel and innovative high-pressure AEMWE stack technology was designed and assembled with all materials from the project (membrane, electrodes, PTL) selected in upscaled size for 200 cm² cells. Tests of the 5-cell stack started with best cell achieving 0.91V@0.5A/cm² but the test had to be stopped after 312 hours.
To address the costs and environmental footprint of AEMWE and compare to other low-temperature electrolyser technologies a techno-economic analysis (TEA) and life cycle assessment (LCA) were performed. It was found that the costs and environmental impact of electricity cause the highest impact independent of electrolyser technology even with the best renewable Electricity.
